/*
 * Copyright 2017 StreamSets Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.streamsets.pipeline.lib.io;

import java.io.Closeable;
import java.io.IOException;
import java.util.Map;

/**
 * The lifecycle of a file context provider is:
 *
 * repeat as needed:
 *
 *    setOffsets()
 *    loop while disFullLoop()
 *      next()
 *    optionally call startNewLoop() and do a new loop
 *    getOffsets()
 *
 *  close()
 *
 */
public interface FileContextProvider extends Closeable {

  void setOffsets(Map<String, String> offsets) throws IOException;

  FileContext next();

  boolean didFullLoop();

  void startNewLoop();

  Map<String, String> getOffsets() throws IOException;

  Map<String, Long> getOffsetsLag(Map<String, String> offsetMap) throws IOException;

  Map<String, Long> getPendingFiles() throws IOException;

  void purge();

}
